Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
Non-invasive procedures may involve making observations underneath the skin of a mammal without breaking the skin of the mammal. Various non-invasive procedures today face challenges with the detection of an object underneath the skin. For example, an object may include a foreign object such as a catheter or a stent. In other instances, an object may include a gall stone, a salivary duct stone, various tissues, a blood vessel, plaque, and/or a bone fragment, among other examples.
In one particular area of study, minerals and salts in kidneys may cluster and form crystals in urine, accumulating into kidney stones. Small kidney stones may be able to pass out of the body with urine, possibly unnoticed. However, larger kidney stones may block, stretch, and/or irritate a tube called the ureter that connects the kidney to the bladder. Passing larger kidney stones through the ureter may cause excruciating pain. Notable symptoms have been described as radiating pain starting in the lower back and then continuing on to the groin and genitals as the kidney stone passes with urine out of the body.
The prevalence of kidney stone disease is increasing in humans. Considerable studies have shown a moderate growth in the percentage of the population affected by the disease. Further, additional studies have indicated that approximately half of newly diagnosed patients will have a recurrent stone within five to ten years of detecting a first kidney stone. In particular, recurrent stones may develop due to residual crystals continuously growing over time.